1. Field of the Invention
The present invention relates to a substrate processing apparatus for performing a series of processings including heating, cooling and a processing with a processing liquid on a thin-plate type substrate (hereinafter simply referred to as "substrate") such as a semiconductor substrate or a liquid crystal glass substrate, and a substrate transport apparatus and a substrate transfer apparatus employed therein.
2. Description of the Background Art
In general, a substrate processing apparatus of the aforementioned type performs a series of substrate processings by circularly transporting a substrate between a heating unit for heating the substrate, a cooling unit for cooling the same and a chemical processing unit for processing the substrate with a chemical liquid by a substrate transport robot.
In a conventional substrate processing apparatus, for example, a plurality of sets of multistage units formed by stacking various types of single-substrate processing units in multiple stages are arranged around a substrate transport robot, which is provided at the center of the apparatus to be vertically movable and swingable. The multistage units, which are formed by stacking the same types of processing units in multiple stages, are separated into a multistage thermal processing unit formed by stacking only a plurality of thermal processing units for heating and cooling a substrate in multiple stages and a chemical wet processing multistage unit formed by stacking only a plurality of chemical wet processing units in multiple stages.
However, the aforementioned substrate processing apparatus obtained by stacking the same types of processing units in multiple stages is inferior in maintenance particularly in upper-stage processing units in relation to the chemical wet processing multistage unit, due to handling of the chemical liquid.
Further, a plurality of sets of multistage units are basically separately arranged around the substrate transport robot provided at the center of the aforementioned substrate processing apparatus, and hence the degree of freedom generally tends to reduce in arrangement of the processing units, to result in disadvantageousness in attainment of functional design responsive to set conditions and effective transportation/processings responsive to the object.
In addition, the aforementioned substrate processing apparatus vertically drives the substrate transport robot with a ball screw. Thus, the substrate transport robot must be extracted upward in maintenance of the processing units, to result in inferior workability in maintenance.
Further, the aforementioned substrate processing apparatus must sufficiently ensure the stroke of an arm of the substrate transport robot, so that the substrate transport robot can access all processing units forming the plurality of multistage units arranged around the same. Thus, the arm of the transport robot or the like increases in size, and the overall substrate processing apparatus also increases in size for ensuring a swing space therefor.